Obstruction by 1B

[ss17]

Basketball referee, baseball coach, so I'm not as aware of all of the rules as I would like to be. This situation came up in one of my games, and the field umpire and I had differing opinions.

R1 gets a base hit to left field, and jogs to 1B. While making his normal round, he bumps into F3 (my First Baseman). After the play was over, and the runner was back at the base, the Field Ump yells that obstruction occurred and awared the runner 2B. I went out and argued that the runner had no intent to get to 2B, nor would he have ever made it to 2B had the 'bump' not occurred. He first stated that the runner did try to go to 2B, then he retracted and said that it didn't matter, and told me to "Learn the rules."

I wasn't totally sure on this one, and tried to google the answer, but I figured I would check on here. I did not trust this guy because he totally blew two different rule interpretations later, so he became totally uncredible.

Basically, I am looking for the Fed explanation of what exactly obstruction is, and if I had a legitimate argument with the guy.